Pneumatic hammer.



PATBNTBD MAY 29, 1996.

E. C. MEISSNER. PNEUMATIC HAMMER.

APPLIGATIUN FILED Nov.12, 1900.

? @gli 6 7 .,f//J7//Vl//zf/l/f//l//l//f bri/UUR /suff No. 822,146.PATENTED MAY 29, 1906.

E. C. MEISSNBR. A PNEUMATIG HAMMER.

Arrmoulox FILED Bov.12, 19.00.

2 SHEETS-SHEET 2.

Ihren/r.'

TED STATES PATENT CEEICE.

EDWARD C. MEISSNER, OE ST. LOUIS, MISSOURI, ASSIGNOR, BY MESNEASSIGNMENTS, rIfo CHICAGO PNEUMATIC 'TOOL COMPANY, A CORPO- RATION- OENEw JERSEY.

' PNEUMATIG HAMMER. f j

EL No..822,146; .Specification of Letters Patent.- 'i VIa-.texited.MaySQQ-I19O. Appiicauoumeanovgmbe'r12,19o. smania. 36,212;

= T0 dll wil/0m it may @1000m/f' form of construction-as to thesupplemental Be it known that I, EDWARD C. MEISSNER, exhaust, in whichthe exhaust passes' to.thej .5 5 .a citizen of the United States, and aresident atmosphere directly or transversely throughf.` I' ofthe city ofSt. Louis and State of Missouri, a wall ofthe cylinder.

5 have -invented vcertain new and useful lm- The principal elements ofmy construction y; rovements in. Pneumatic Hammers, of are a handle, avalve-bushing 2,'Fig. 10, .1n-n y ,l Vwhich the following is aspecification. closed in said handle, a valve 3, Fig. 11, in 6o Myinvention relates to what are comsaidbushing, a barrel oroylinder'4-,1-clamped monlyknown as pneumatic hammersgand to said?handle in alinement therewith, l" -1 'o lthe object thereof is toproduce a hammer of 1, 2, and 12, and a pston in said cylinder. thischaracter having novel and advanta- VThe motive fluid employed will conjgeous features of construction and operation venience be referred toascompre'ss' air] 65 U -wl1ich. will be apparent from the descriptionThe handle comprises a:grasping"iportion-`z i hereinafter given. and acylindrical portion Yhavin ajcy-lindlfie'a Chief among the advantagesof'my hamsocket extending nearly the fulllengt'hth 'I ,ner may bementioned, first, a novel 'and eili-` g of, Fig. 12. The `purposeiofthis:,so'ek'eigy cient valve and valve movement 5 second, the containtheivalveand valv -bushing; biitffor v7o'.; "provision of supplementalexhaust and, reasonspof economy f, and c.onvenience". "go third,'jtheprovision of means for cushioning manufacti'iije-it is preferable to fitasepflrate-f-jl he rearward stroke of the.. piston orplungerfi'vcylindrical sleev'e or socket piece 1' injthe inthe presentinstance 1`l1ave shown `my vsocket ofthehandle rathe'thanmount the."A ,Ynventin-embodied-inwhat isdlesgnated a valve-bushing directly inthe'handlefscket- 7 5 longistrokdfor "'riveting. hammer, in itself.Thissocket-piecelis, in eecttaf 'art which the piston has a length ofstroke ofthe handle and constitutesla valve ck; j greater thanfitsownlength and in which my The bushing 2 iits in the rear end nventionvfindsuseful application; but my socket, and the end ofthe barrel or cylinv'rl 1 nventiony isf-not limited to this Species of 4 is reduced to lit'into the fore end of .saidf Y8o hammer.` Y socket-piece and abut alainsi; the endof they thev accompanying drawings, which bushing, theloore at t e fore end of/ said-f formpart 'fof this specification, andwherein socketiece being enlarged to accommodate.

ocfcur,'Figure 1 is a central longitudinal secsurface of saidcylindrical ortionof'thehan- -8 5 tin.pf my device, Showing the valve inits dle is threaded to alloWa t eaded sleevel to?4 fj rearmost oropenposition. Fig. 2 is a simiwork thereon, and the front end of-Said3511er. view showing the valve in its foremost sleeve has aninwardly-extendin "ange 7 .orclosed-pcsition.' Fig. Sis across-sectionalwhich overlaps and engages aL s oulderf" view on the dotted line 3 3 ofFl.g.l. Fig. 4 formed on the cylinder in posti'on tofabu lis across-.sectional view on .the lince 4 ofv against the end of thclmndlef-The rearend Fig. 1; Fi 5 is a cross-sectional view on the of said sleeveis provided with ratchet-teeth" 40 line -5 5 of vig. 1. Fig'. 6 is across-sectional 9, Fig. 9, anda spring-pressed boltlO, 'ro-. view on theline 6 6 of Fi 1. Fig. 7 is 'a' vided with ratchet-teeth 11 in'its e'n,ris cross-sectional 'View on the line 7 7 of Fig. 1. mou Ited on thehandle position to' e11' -95 Fig. 8 is a crass-sectional view on theline 8 8 ga e the .teeth on said collar, and thereby of Fi 1. Fig. gis@detail side viewshowing loc i said-collaragainst rotation, f 1 45theevice for preventfrng the unlocking of Thef-valve-bush' g 2 is acylindrical .sleeve Athe threaded collar. Fig. 10 is a sectional iittintightlyinthesocket-pieceofthehadle, l detail view of the valve-bushing.Fig. 11 is a Yand t e valve 3 isa cylindrical vpiece"J fitting roosectional detail view of the valve. Fig. 12 in' said bushing and movableendwise thereisnan enlarged.l longitudinal section of the in. Thevalve-bushing has holes extending '50*v` upperend of the hammer with theparts through the sidev thereof and loca-ted -as fl' in thepositionsshown in Fig. 1; and Fig. lows, Figs. 10 and 12: One ofsaid holes 12 A13, Ia section of the intermediate portion oi' is located back of therearmost position of the 1, o5f. `'.thecylinder or barrel, illustratinga mndifv'. valve. and the other holes 13, 14, 15,. 116, '17,*

ab@ n likesymb'ols refer to like parts wherever they said re uced end ofthe cylinder. The outer f "Il :l

and 18 are opposite the valve in its advanced covered when the valve isin its rearward position, Fig. 12. Back of the admission-port 13 arethree ports 15, 16, and 17, the foremost, 15, of which communicates witha passageway 20, extendin longitudinally through the wall of the vave-block and the wall of the cylinder, and terminating in a port 21 inthe forward end of the cylinder. The rearmost, 17, of said three portscommunicates with a passage-way 22, extending longitudinally through thewall of the valve-block and thewall of the cylinder and terminating in aport 23, formed in a circumferential groove 1n the cylinder, near therear end thereof. Themiddle port 16 of said three communicates withtheatmosphere through a passageway 24 in the valve-block and handle andconstitutes the main exhaust-port of the device. Two grooves 25 26 areformed in the valve 3 in position.' to register alternately with theexhaust-port 16. The front groove 25 registers at all times with theforemost, 15, of said three ports, and the rear groove 26 registers withthe rearmost, 17 of-said three ports at all times. By this constructionthe front end of the cylinder is vented or exhausted through the port21, passage-way 20, port 15, groove 25, and the main exhaustport 16 andpassage-way 24,.when the valve 1s in its rearward position, Figs. land12, admitting live air to the rear of said cylinder, and when the valveis in its forward position, Fig. 2,-tl1e rear portion of the cylinderisopen to the atmosphere through port 23, passageway 22, port 17, groove26, main exhaustport 16, and passage-way 24.

vIn order to effect the movement of the valve 3, an annular rib 27 isformed on the rear end thereof, Fig.- 11, whereby zthe cross"- sectionalarea of the rear end exceeds that of the front end. In other words, thevalve is of the differential type, whose larger pressure area in thepresent instance faces rearwardly and whose smaller ressure area facesforwardly., The bore of t e bushin is enlarged at the rear end to'form acham er or space to; accommodate said rib, Fig. 10, and the shoulder 28thus formed in said bushin limitsthe forward movement of the va ve. Therearward movement of -said valve is limited by a hollow or concaved lugor cap 29 in the end of said bushing and aving a flange extending overthe end thereof.

The outer front ledge of this-cap is recessed,A

the barand notches or holes 30 are formed in said end and lie oppositethe rearmost port 12 in the bushing. `From this ort -12 a passa eway 31extends through t e handle and t e wall of the cylinder to a port 32 inthe middle portion of the cylinder between the ports 21 to 23,hereinbefore mentioned. In the operation ofthe device as soon as thepiston or plunger'5 in its forward movement uncovers the intermediateport 32 air from the cylinder flows through said port 32, passage-way31, and port 12 into the space in the rear of the valve 3 and exertspressure upon the rear end of said valve. Both ends of the valve arethus submitted to pressure from the same source; but the ressure on therear end of the valve exceeds t at on the front end by reason of thearea of the rear end being the larger. Consequently the valve movesforward to the positionillustrated in Fig. 2 and shuts ofl` theadmission of air into the rear end of the cylinder. A vent-hole 33,formed throu h the handle and the bushing at the shouler thereof,permits the admission and escape of air in front of the rib 27 on said-valve, andfthus keeps the pressure thereon' constant.

The return of the plunger is effected by live'air admitted into thefront end of the of a tool or button set 34 fits therein tiofht enoughto secure a sufficient pressure. Trliis live air enters the front end of`said cylinder throughl the duct or passage-way 20, which communicateswith the ort 15 of the bushing in frontv of the main exhaust-port 16.For this purpose a small port 14, Fig. 10, communicating with the mainair-duct 19 is formed vin the bushing 2 back 'of the main admission-port13 in position to register with the first groove 25 of the valve in theforward position thereof and in position to be closed y the end portionof said valve in the rearward position thereof. By this arrangement assoon as the valve is moved forwardly to close the main admission-port 13tothe rear end of the cylinderand bring-its front groove 25 intoregister with the small port 14 of the su ply-duct, Fig. 2, live airenters the front en of the cylinder through the small duct 14, frontgroove 25 ofthe valve, port 15,

passagefway 20, andl port 21. As the rear end of the cylinder is open tothe atmosphere while the valve is in its forward position, the airadmitted through the small duct 14 into the front end of the cylinderforces the piston rearwardly. In order -to prevent the accidental returnof the valve to its rearward position, the small duct 14 is bored atsuch an angle `as to cause the air flowing therethrough to impingeagainst the front wall of the front groove o the valve, whereby thepressure on said front wall is greater than the pressure on the rearwall. i v

' .In addition to the exhaust through the` IOO IIO

` from the valve into the cylinder,

seal-i6 l lead directly through the wall of the cylinder,-

as illustrated in Fig. 13; but it is preferable to have it extendlongitudinally through the -wall thereof and through the handle, as inFigs. 1, 2,.and 12,so that the expelled air will not interfere with thework. As clearly illustrated in Figs. 1 and 2, taken vin connectionwithFigs. 4, 5, and 6, a supplemental exhaust'- passage 56 extends from itsport 55 rearwardly through the body or wall of the barrel or cylinder,through the reduced rearward end of such cylinder, Fig, 4, through aportion of the cylindrical socIiet piece or bushing 1 and then emergeson the inner wall of said socket piece or bushing in position toregister with the circumferential groove 16, which is in constantcommunication with the main or regular exhaust-port and passage 24, asclearly illustrated in Fig. 6. Obviously the outlet end of passage 56may be differently positioned for communicating with the outer air, ifdesired. The functions of this supplemental exhaust are to release thepressure at the front end of the cylinder before the piston completesits return stroke, so that said piston will not have a forcible impactat the rear limit of its stroke to decrease the resistance to theadvancing piston by increasing the rapidity of exhaust from the frontend of the cylinder, also to cooperate with the main exhaust-port inreleasing the pressure at the rear end of the cylinder just before thepiston reaches the limit of its forward stroke, whereby the pistonrebounds freely after its impact, and thus avoids objectionable jarring.Y

In order to protect the valve against the possibility of impact of thepiston, the rear end of the cylinder is closed by a plate or block 60,hereinafter designated a cushionplate. This plate consists of animperforate circular body portion and an annular portion on the rearface of said body portion. The outer diameter of 4the annular portion isllarger than that of the body. The bore of vthe cylinder is enlarged atthe rear end and the annular portion of the plate fits in said bore andabuts against the shoulder formed by such enlargement. In order to admitair a slot 61 is cut in the annular portion of said plate in registerwith a slot or port in the end of the cylinder. This last-mentioned slotcommucates with a passage-way 62, extending forwardly inthe wall of thecylinder, and opening into said cylinder through a port 63 a suficientdistance from the end thereof to affordV a suitable cushion for thepiston, as hereinpressure after described. By this arrangementA the airadmitted in the rear of said cushion-plate passes through the slotthereof and thence f through the passage-way in the cylinder-wall andenters the cylinder near the rear end thereof. In operation the pistonupon its return stroke closes the port 63 of the passage-way 62. The airthus confined in the rear end of the cylinder is compressed to fa higherdegree than the normal or ordinary working and not only constitutes apositive cushion, but initiates the forward movement of the piston anddrives it far enough to uncover the admission-port 63.

' It is desirable in ariveting-harnmer-to have a button set incorporatedas a part thereof. v

For this purpose a nosing or sleeve 3 5 is inserted and rigidly securedin the end of the cylinder. The projecting end of this sleeve isenlarged and has a groove 36 formed in the periphery thereof. In thisgroove fit the flanges 37 of two semicircular pieces 38, which projectbeyond the end of the nosing. These pieces 38 are firmly clamped inplace by a strong circular spring or resilient split ring 39,which restsin ooves 40,provided therefor in the outer sur aces of said pieces,whereby said pieces constitute clamping-jaws for holding the shank ofthe button Set or tool, Figs. 1 and 3. In order to better perform thisfunction, each of the clamping-jaws is provided with a groove 41 on itsinner face and the shank of the button set or tool is provided with arib 42 for interlocking therewith, said rib and grooves being preferablybeveled to facilitate insertion and removal of the button The shank ofthe button set fits in the nosing tight enoughl to insure the retun ofthe piston, but the rib and grooves are arranged to permit a slightendwise movement of the shank.

The admission of air is controlled by a throttle-valve in the handle.This valve is a hollow cylindrical cup 43, ittin in a tubular sleeve 44,which is set into a cy indrical bore in said handle. The middle portionof this bore is enlarged to form an annular oove 45 around said sleeve,and the sleeve 1s provided with a series of perforations 46 in registerwith said groove. The outer end of said bore is threaded and is closedby a threaded cap 47, fitting thereon and constituting an abutment for ahelical spring 48, which rests inside of said sleeve and bears againstsaid cup. The admission-duct 19 extends from a tap at the side of thehandle into the groove around said sleeve and from the bottom of thebore to the main-valve admission-port 13. The spring keeps the valve-cupnormally in its advanced position, so that its sides close theperforations in the sleeve, and the air is admitted or shut off at theperforations in the sleeve according as the valve-cup is in its backwardor advanced position. The movement of the valve-cup is effected by alever set or other tool.

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; the operator.

formed in said handle to admit a short rod 49, mounted on the handle inposition to be conveniently manipulated by the thumb of For this purposea-hole 1s 50, which extends from the lever to the cup, whereby'themotion of either is transmitted to the other. In order tovequalize thepressure on the opposite sides of the valve-cu a small hole 51 is formedthrough the en of said cup. Y l

For the sake of clearness, brevity, and convenience of description theforegoing specification assumes thateach port and each passage-way havea separate function from the others. In practice, however, it is betterto form circumferential grooves inthe valvebushing at thepointshereinbefore designated for the several orts and to have aplurality -of ports extendlng through the bushing from `the bottom ofeach groove. This construction not only balances the pressure on theside of the valve and provides a large port area, but also avoids thenecessity of having the ports made to registe So, too, instead of singlepassage-ways above described a plurality of passage-ways may be used foreach. The operation of my hammer. is as follows: Upon the manipulationof the lever 49 'the throttle-valve in the handle is opened so as 3o toadmitv live air through the air-supply duct 19. When the valve is in itsrearmost posi- ,hp

pressure in the rear end of the cylinder to retion, as shown in Figs. 1and 12, the air-supply duct 19 communicates with the rear portion of theYcylinder through the port 13 4in advance of its front endand thepassage-way l62around the cushion-plate, and live air is admitted intosaid cylinder through said port 13 and passage-way 62. In this positionof the valve the front end of the cylinder is open to the atmospherethrough the port 21 in its end, the passa e-way 20, the port 15 in thevalve-bushing, tIie front groove 25 of the valve, and the mainexhaust-port 16 in the bushing and exhaust port or .ports 24, throughthe handle-socket to the atmos here. -The front end of the cylinder isalso ectly open to the atmosphere through the-port 55 and passage-way56. The live air admitted in the rear portion of "the cylinder thereforedrives the piston forwardly without affecting the position of the valveuntil it passesand uncovers the port '32. When the port 32 is uncovered,the live air in the rear portion of the cylinder passes therethrough andthrough the passage-way 31 and the port 12into the -space or chamber inthe rear of the valve. As

the rear end of the valve is of larger area than` the front end andyboth sides are submitted todirect or cylinderpressure, the valve fis'driven forwardly to the position illustrated in Fig. 2. This movement ofthe valve closes tlr'emain admission-port 13, and at the same time itopens communication between the main exhaust-port 16 and the port 17,which'l communicates vthrough the passage-way 22 and port 23 with therear portion of the cylinder. At the same time the front port 21 of thecylinder and its passage-way 20 are cut off from the main exhaust port16 and brought into communication through the front groove 25 of thevalve with the small port 14, communicating with the air-supply duct, sothat live air is admitted to the front end of the cylinder. By thisarrangement the air is cut off from the. rear of the piston andadmittedto the cylinder in front thereof before it reaches the limit of itsstroke. The theory of this arrangement of ports is that by 'the time thepistonis passing the port 32 it has acquired a very rapid speed, and itsmomentum will carry it a considerable distance before the air admittedthrough the port 32 shall have had time to effect the movement of thevalve, so that the piston will impart its stroke with very littleresistance by reasonof air being admitted in front-of it. In thisforward movement of the piston the supplemental exhaust-port 55 servesto increase Y the rapidity of exhaust from the front end of the cylinderuntil the piston is nearing the limit of its stroke, and after the rearend of the piston has passed said port 55, said port serves to releasethe pressure in the rear of said piston, whose motion at this time iscontinued by its own momentum. When the iston delivers its stroke, there.is very little sist its rebound, and at the same time live air is beingadmitted in the front end of the cyla inder to effectthe return of thepiston. At the beginning of the return stroke of the piston the rearportion of the cylinder is vented lthrough the port 23, passage-way 22,port 17 of the bushing, rear groove 26 of the valve and mainexhaust-port 16, and also through the supplemental exhaust-port 55 andpassage-way 56. The supplemental exhaustport 55 is closed near thebeginning of the backward stroke; but no effect is produced on the valveuntil the piston covers the port 23. When, however, the piston coversthe port 23, the escape of air from the rear end of the piston-chamberby the exhaust is cut 0H and the further rearward movement of the pistoncompresses the air sufiiciently to cause it to return the valve to itsrearward position, Fig. 12, the pressure passing from the pistonchamberto the front end of the valve-chamber for that purpose through the port63, passage 62, and port 61. In order to insure the return of the valvelat the proper time, the valve may be loosely fitted in the bushing, ora port 64 may be drilled in the bushing from the admission-port throughthe front end of the bushing, Fig. 10, so as to remain uncovered by thevalve at all times. By this arrangement live air is always bein admittedvin front of said valve without pro ucing any rearward position.

port 23 is closed by the piston, as in Fig. 12, the live air in the rearof the piston coperates with the air compressed by the returning pistonto force the valve backwardly into its When the valve is thus forcedback, it is in the position shown in Figs. 1 and 12 and ready to renewthe operation hereinbefore described. The piston on its backward strokepasses the port 63, and thereby prevents the admission of'air back ofthe piston; but the initial forward movement of the piston is effectedby the expansion of the air confined and compressed in the rear end ofthe cylinder by the return stroke of the piston.

As hereinbefore suggested, the supplemental exhaust instead of? beingled rearwardly through the body of the cylinder to the main .or regularexhaust 24 may be led directly to the atmosphere by a port or passageextending laterally through the wall of the cylinder, as' clearlyindicated in Fig. 13, in which such supplemental exhaust-port is shownat a.

p What I claim is- 1. A pneumatic hammer comprising a cylinder havingports for the admission and escape of air, a piston in said cylinder,and a valve for controlling the admission andrelease of air, saidcylinder having a supplemental exhaust-port located in the forwardportion thereof in position to be uncovered by the piston shortly afterthe initiation of its return movement and before the comple- `tion ofsuch return movement, substantially 5 as described.

2. A pneumatic hammer comprising a cylinder having ports for theadmission andI escape of air, a piston in said cylinder, and a valve forcontrolling the admission and release of air, said lcylinder having asupplemental exhaust-port located in the forward portion thereof inposition to be uncovered by the piston shortly after the initiation ofits return movement and before the completion of such return movement,said supplemental exhaust-p ort being permanently op en `to theatmosphere,substantially as described.

3. A pneumatic hammer comprising a cylinder having ports for theadmission and release of air, a piston in said cylinder, a handleportion fastened to said cylinder and having a cylindrical socket-piececlosed at one end and nested therein, and a cylindrical valve in saidsocket-piece in alinement with said cylinder, said valve having groovesin its side to coperate with the inlet and exhaust ports, substantiallyas described.

4. A pneumatic hammercomprising a cylinder having ports for theadmission and release of air, a piston in said cylinder, a handleportion fastened to said cylinder and having a cylindrical socket-piececlosed at one end and nested therein, said cylinder having a reduced endportion fitting within said socketpiece, and a cylindrical valve in saidsocketpiece in alinement with said cylinder for controlling the inletand exhaust ports, substantially as described.

5. A pneumatic hammer comprising a handle portion having -ports for theadmission and release of air, a cylinder, a piston in said cylinder andan imperforate valve for controlling the admission and release of air,one of said ports being in the rear of said valve and communicatingthrough a passage-Way with the middle portion of said cylinder, saidvalve having two grooves in its side for coperation with some of saidports, and having its rear end of larger diameter than its front end,substantiallyas described. y

6. A pneumatic hammer comprising a`c'ylinder having ports for theadmission and release of air, apiston in said cylinder, and a handleclamped to said cylinder and having a cylindrical socket portion, theouter portion of said socket being enlarged and the end of said cylinderbeing reduced to iit tight therein, and a valve-bushing in the rearportion of said socket provided with portsfor the admission and releaseof air, anda lon itudinally-movable valve in said bushing a apted tocoperate with said bushing-ports, substantially as described.

7. A pneumatic hammer comprising a cylinder, a piston therein, a handlehaving a cylindrical socket portion, a valve-bushing in said socket anda valve in said bushing, the rear end of said valve being enlarged andfittinor in the enlarged bore of said bushing, and

thebfront end of said valve fitting loosely in IOO said bushing topermit the leakage of air by said front end, said hammer being providedwith ports and passage-ways arranged lto be controlled by said valve andsaid piston, substantially as described.

8. A pneumatic hammer comprising a cylinder having ports for theadmission and release of air, a piston in said cylinder, and a valve forcontrolling the admission and release of air, said cylinder havin asupplemental exhaust-port located in t e forward portion thereofimfposition 'to be uncovered by the rear end of the piston shortlybefore the forward limit of the piston-stroke, and by the front end ofthe piston soon after the beginning of its rearward stroke,substantially as described.

9. A pneumatic hammer comprising a cylinder having ports for theadmission and release of air, a piston in said cylinder, and a valve forcontrollin the admission and release of air, said cy inder havin a supplmental exhaust-port located in t e-forward portion thereof in positionto be uncovered by the rear end of the piston shortly before the forwardlimit of the piston-stroke and by its front end shortly after thebeginning of its rearward stroke, said supplemental exhaust-port beingpermanently open to the atmosphere, substantially as described..

10. A pneumatic hammer comprising a cylinder having ports for theadmission and release of air, a piston in said cylinder, and a handleclamped to said cylinder and having a cylindrical socket portion, theouter portion said cylinder being reduced to `it tight therein, and avalve-bushing in the rear portion of said socket provided with ports forthe admission and 'release of air, and having its bore enlarged at therear end, a cylindrical valve in said bushing having a shoulder at itsrear end fitting in the venlarged portion of the bushing-bore and havinggrooves for coperatingwith ports in said bushing, one of the ports insaid bushing being located at the rear of said valve and communicatingthrough a passage-way in the socket portion and cylinder-wall with` aport near the middle portion of the cylinder, substantiallyas'described. i v

12. A pneumatic hammer comprising al cylinderhavingports fortheadmission and release of air, a piston in said cylinder, and a handleclamped tosaid cylinder and having a cylindrical socket portion, and avalvebusliing in said socket provided with Aports for the admission andrelease of air and havv in its bore enlarged at the rear end, acylindrical valve in said bushing `having a shoulder at its rear endfitting in the enlarged portion of the bushing-bore and having groovesfor cooperating with ports in said bushing, one of the ports insaid'bushing being located at the rear 'of said valve and communicatingthrough a passa e-way in said socket portion and cylinder-wa l with aport near the middle portion of the cylinder,- substantially asdescribed. V t K 13. A pneumatic hammer comprising a cylinder, a pistontherein, a handle portion fastened to said cylinder and having a socketconstituting a continuation ofthe cylinderchamber, a valve-bushing insaid socket, and a valve in said bushing, said valve having twocircumferential grooves and being enlarged at its rear end, and saidhammer having a passage-way extending from the rear of said valve to themiddle rportion of said cylinder, and a main admission-port in positionto be covered by the front end of said valve in its forward position andto be uncovered when the-valve is in its rearward position,y

and a main exhaust-port in position to register'with the two groovesalternately, and a.

passage-way extending from the front end ofl the cylinder to a portwhichregisters with hammer comprising a -the front groove of 'the valve, anda passageway which extends from the rear portion of the cylinder to aport which registers with lthe rear groove of the valve, and asupplemental admission-port in position to register with the frontgroove of the valve when said valve is in its forward position,substantially as described.

14. A pneumatic hammer comprising a cylinder, a piston therein, a handleportion' fastened to said cylinder and having a socket portion, 'avalve-bushing in said socket, and a valve in said bushing, said vvalvehaving two circumferential grooves and being enlarged at its rear end,and said hammer havl ing a passage-way extending from the rear of saidvalve to the middle portion of said cylinder, and a main admission-portin position to be covered by the front end of said valve in its forwardposition and to be uncovered when the valve is in its rearward position,and a main exhaust-port in position to register with the twogroovesalternately, and a passage-way extending from the front end ofthe cylinder to a port which registers with 'the front groove of thevalve, and a passageway which extends from the rear portion of thecylinder to a port which registers with the rear groove of the valve anda supplemental admission-port in position to registerY with the frontAgroove of the valve when said valve is in its forward position, and asupplemental exhaust-port leading from the middle portion of thecylinder to the atmosphere, substantially as described.

15. A lon -stroke pneumatic hammer comprising a cy inder having itsfront end closed IOC with the shank of a tool, and a handle fastened tosaid cylinder and Vhaving a cylindrical socket portion, a bushing insaidsocket havingits bore enlarged at the rear end, a valve enlarged at therear end and iittingin said bushing, and a piston in said cylinder,said-bushing having circumferential grooves in its outer surface andports extending through said bushing from said groove and arranged to becontrolled by said valve, said hammer having passageways extending fromsaid groove to the atmosphere and to the front and rear ends of thecylinder, and a passage-way extending from the rear of the valve to themiddle portion of the cylinder, substantially as described.

16. A pneumatic hammer comprising a cylinder, a piston therein, a handlefastened to saidcylinder in alinement therewith and having a cylindricalsocket portion, a bushin in said socket and a valve in said bushing,said bushing having circumferential grooves with ports leading therefromto the interior of said bushing, the main admission-ports being inposition to be covered and uncovered by the front end of said valve, andthe rearmost port being at the rear of said valve, and

said hammer having passage-ways extending IIO 'rif

- from three intermediate grooves in said bush-l ing to the front andrear ends of the cylinder and tothe atmosphere respectively,substaninterior of said bushing, the main admissionports being inposition to be covered and uncovered by the front end of said valve, andthe rearmost port being at the rear of said valve, and said hammer havmgpassageways extending from three intermediate .grooves in said bushingto the front and rear ends of the cylinder and to the atmosphererespectively, substantially as described.

18. A pneumatic hammer comprising a cylinder, a piston therein, a handlehaving a A socket, the outer or forward end of the socketpiece beingenlarged and the rearward end of the cylinder being correspondinglyreduced to fit into said enlarged end of the socketpiece, avalve-bushing located in the socketpiece and having ports and passagesfor the admission and exhaust of the motive fluid to and from thecylinder, anda valve arranged in the valve-bushing for governing saidports and passages; substantially as described.

19. A pneumatic hammer comprising .a handle portion having ports for theadmission and release of air, a cylinder clamped to said handle portion,a piston in said cylinder, and a valve in said handle portion forcontrolling the admission and release of air, said valve having a groovetherein and said handle portion having a small duct inclined forwardlyin position to cause the air to impinge against the front Wall of saidgroove, substantially as described.

20. A pneumatic hammer comprising a handle portion having ports for theadmission and release of air, a cylinder clam ed to said handle portion,a piston in said cy inder, and a valve in said handle portion forcontrolling the admission and release of air, said valve havinvr agroove therein and said handle portion thaving a small duct inclined inposition to cause the air to impinge against the wall of said groove,substantially as described.

21. A pneumatic hammer comprising a cylinder, a piston therein, portsfor the admission and release of air, a valve for controlling theadmission and release of air, and a duct leading from the air-supplyduct and opening in position and direction to cause the air to impingeagainst the valve in the general direction of its line of motion, sub-vstantially as described.

22. A pneumatic hammer comprising a handle portion having a cylindricalsocket, a

socket-piece therein, abushin in said socketpiece and a valve in saidbus g, and a cylinder clamped to said handle portion in alinementtherewith, and a piston in said cylinder, said bushing, handle portionand cylinder having continuous passage-Ways therethrough for theadmission and release of air, and al of said passage-Ways beingcontrolled entirely by said valve and piston, substantially asdescribed.

23. A pneumatic hammer comprising a handle Cportion having ports for theadmission an said cylinder, and a valve for contro ling the admissionand release of air, said valve being located back of said cylinder andin alinement therewith, and an imperforate plate in the rear end of saidcylinder, substantially as described.

24. A pneumatic hammerv comprising la cylinder having ports for theadmission and release of air, an imperforate plate at the rear end ofsaid cylinder, a iston in said cylinder, and a handle clam e to saidcylinder and having a cylindrical) socket portion, a valvebusning insaid socket portion, and a valve in said bushing in alinement with thecylinder, the pressure-admission ort extending from the space back ofsaid p ate to'a point in the piston-chamber sufficiently far from therear end thereof to constitute an air-cushion therein, substantially asdescribed.

25. A pneumatic hammer com rising a cylinder having passage-Ways for t.e admislsion and exhaust of pressure, and a valve controlling saidassage-ways and constructed to permit lea age of air from thevalvechamber to the rear end of the cylinder; substantially asdescribed.

26. A pneumatic hammer com rising a cylinder having passage-ways for t1e admission and release of air, and a reciprocating valve forcontrolling said passage-ways, said hammer having a passage-wayextending from the supply-duct to the end of the valvechamber beyond therange of movement of the valve, substantially as described.

27. The combination, in an impact-tool, of a cylinder, a pistonreciprocable therein, inlet and exhaust passages for the motive fluid,

and a valve movable in a chamber at one end of the cylinder and servingto control the flow ol motive fluid to and from each end of thecylinder, one face of said valve being ppen to a chamber in which motivefluid 1s compressed by the piston as the latter approaches one end ofits stroke, and the other face of the valve being open to a chamber towhich motive fluid under normal pressure is admitted.

28. The combination in an impact-tool, of

a cylinder, a piston reciprocable therein, inlet and exhaust passagesfor the motive fluid, and a valve movable in a chamber at one end of thecylinder and serving to control the flow release of air, a cylinder, aiston in IOO IIO

motive fluid to lan cylinder, said valve having one face open toi 4achamber in which motive fluid is compressed by the piston as the latterapproaches lone end of its stroke, and another face of :.larger areathan the first open to a chamber p o which motivefluid under normalpressure 29. In a pneumatic tool of the type deio scribed, a valveto,cntrol the admission and exhaustv to and from the cylinder, saidvalve being actuated by direct air-pressure at one stroke of the pistonand by-compression of' the air between 'it and the piston at the returnstroke;

30. The combination in an impact-tool, of a cylinder, a pistonreciprocable therein, inlet and exhaust passages for the motive fluid, avalve movable in a chamber atone end of the cylinder and serving tocontrol the flow of motive fluid to and from each end of the cylinder,said valve having an enlarged head, and one face of the valve being opento a chamber in which the motive fluid is com- 'ressed by the piston asthe latter approaches one end of its stroke, and a passage leadingfromthe chamber which receives the enlarged head of the valve to apoint' in the cylinder where it will be uncovered by the piston 3c whenthe latter reaches the forward limit of its stroke, whereby the valvewill be moved in one direction by motive fluid compressed by the pistonat one end of its stroke, and in the other direction by motive fluidunder normal pressure when the piston reaches the other limit of itsstroke. l 31. In a fluid-pressure-operated tool, the

combination with a cylinder, of a reciprocating piston therein, avalve-casing, a diHerential piston-valve in said casing controlling thesupply and exhaust of fluid-pressure to and from the opposite ends ofthe cylinder, said valve-casing and cylinder having ports and passageswhereby the valve ismoved in one direction by air compressed by thepiston and in the other direction by fluid-pressure flowing through thecylinder from the supplyort. p 32. In a pneumatic hammer comprising acylinder having passage-ways for the admission and release of pressureand a reciprocating'valve for controlling said assage-ways, said valvehaving one end tting against leakage in the valve-chamber andhaving itsother end arranged to permit a leakage of air into one end of thevalve-chamber to insure the movement of said valve, substantially asdescribed.

33. In a pneumatic hammer, a valve to control the admission and exhaustof motive fluid to and from opposite ends of the cylinder, said valvebeing moved in one directionby air compressed by the piston and in theopposite direction by the motive fluid.

' 65 34. In a pneumatic hammer,v a valve to -control the admission andexhaust of motive to one of its pressure areas through a portcontrolledby the piston, to cause the valve to admit motive fluid in front of' thepiston to v drive the latter rearward, and being shifted in the oppositedirection by air compressed by the piston at its backward stroke, toadmit motive fluid to the rear end of the cylinder to drive the pistonforward again.

35. In a pneumatic hammer, a differential valve to control the admissionand exhaust of motive fluid to and from the opposite ends of thecylinder, said valve being moved in one direction by air compressed bythe piston and in the opposite direction by the motive fluid.

36. In a pneumatic hammer, a differential valve to control the admissionand exhaust of motive fluid to and from the opposite ends of thecylinder, said valve being moved in one direction by motive fluidadmitted to the larger pressure area of the valve at the forward strokeof the piston, and in the opposite direction by air compressed by thepiston at its return `stroke and acting upon the smaller pressure areaof thevalve. l

37. In a pneumatic hammer, a valve to control the admission and exhaustof motive fluid to and from the opposite ends of the cylinder, saidlvalve being located at the rear end of the cylinder and in linetherewith and moved in one direction by air compressed by the piston andin the opposite direction by the motive fluid.

38. In a pneumatic hammer, a differential valve to control the admissionand exhaust of motive fluid to and from the opposite ends of thecylinder, said valve being located at the rear end of the cylinder andin line therewith and moved in one direction by motive fluid admittedtoits larger pressure area at the forward stroke ofthe piston, and inthe opposite direction by air compressed by the piston at its returnstroke and acting against the smaller pressure area of the valve.

39. In a pneumatic hammer, the combination of a cylinder, a pistontherein, a valve for controlling the movements of the piston and havingone of its pressure areas in communication with the rear end of thepistonchamber, means for admitting motive fluid to the opposite pressurearea of the valve, and an exhaust-port for the rear end of thepistonchamber arranged to be closed by the piston during its returnstroke to cause the air compressed by the furthermovement of the pistonto shift the valve.

40. In a neumatic hammer, the combination of a cy inder, a pistontherein, a differential valve for controlling the movements of thepiston, and having its smaller pressure area in communication with therear end of IOO IIO

IIS

ta-Wc) thepiston-chamber, a ort and passage leading ,from the piston-camber to the larger pressure area of the valve and arranged to beuncovered by the piston at its forward stroke,

andv anv Aexhaust-port for the rear end of the piston-chamber arrangedto be closed by the piston during its return stroke to cause the air comressed by the piston during its further movement to shift the valve.

41. In a pneumatic hammer, a valve to control the admission and exhaustof motive fluid to and from the opposite ends of the cylinder, saidvalve being shifted in one direction by motive-fluid pressure at theforward movement of the piston and in the opposite direction by aircompressed by the piston at its return stroke, and means for permittinga leakage of motive fluid into the rear end of .the piston-chamberduring the return stroke of the piston.-

42. In a neumatic hammer, the combination of a cy inder, a pistontherein, a valve for controlling the movements of the piston and havingone of its pressure areas in communication with the rear end of thepiston-chamber, a port controlled by the piston for admittin T motivefluid to the opposite pressure area ofthe valve at the forward stroke ofthe piston, an exhaust-port for the rear end ofl the'piston-chamberarranged to be closed by-th piston during its return stroke, and meansfor permitting a leakage of motive fiuid into the rear end of thepiston-chamber during the return stroke of the piston.

43. In a pneumatic hammer, the combination of a cylinder, a pistontherein, a differential valve for controlling the movements of thepiston and having oneI of its pressure areas in communication with therear end of the piston-chamber, means for admitting motive luid to itsopposite pressure area, an exhaust-port for the rear end of thepistonohamber arranged to be closed by the piston during its returnstroke, and means for permitting leakage of motive fluid into the rearend of the piston-chamber during the return stroke of the piston.

44. In a neumatic hammer, the combination of a cy inder, a pistontherein, a differential valve for controlling the movements of thepiston and having its smaller pressure area in communication with therear end of the iston-chamber, a port and passage leading om thepiston-chamber to the larger pressure area of the valve and arranged tobe uncovered by the piston at is forward stroke, an exhaust-port for therear end of the pistonchamber arranged to be closed by the piston duringits return stroke, and means for permitting a leakage of motive Huidinto the rear end of the piston-chamber during the return stroke of thepiston.

45. In a neumatic hammer, the combination of a cy inder, a piston ofuniform diameter therein, a valve for controlling the admission andexhaust of motive fluid to and from the opposite ends of the cylinder,and a passage leading from one pressure area of the valve to thepiston-chamber and opening into the latter by a port uncovered by therear end of the piston at 'the forward stroke of the latter, to admitmotive iuid from the piston-chamber to said pressure area of the valve,and uncovered by the front end of the piston at the rearward stroke ofthe latter to ermit said motive fluid to exhaust into the ont end of thepiston-chamber.

46. In a neumatic hammer, the combination of a'cy inder, a pistontherein, a valve block or bushing at the rear end ofbhe cylinderprovided with a series of ports and as sages communicating with themotiveuid supply, the front end of the cylinder, the atmosphere, and therear end of the cylinder, respectively, and a valve operating in saidvalve block or. bushing and having along its length two grooves orrecesses for governin said series of ports, said valve having one encglexposed to the rear end of the iston-chamber and its other end incommunication with the piston-chamber through a port controlled by thepiston.

47. In a pneumatic hammer, the combination of a cylinder having apiston-'chamber and ports for the admission and exhaust of the motiveiiuid, means for closing the rear end of the chamber to form anair-cushion therein, a valve for controlling saidl ports and arranged inrear of the piston-chamber, the inlet-port openin into thepiston-chamber at a point forwar of the rear end thereof so as to forman air-cushion therein, and a piston operating to close said inletort onits rearward stroke and be cushione rapped in the rear end of thepiston-cham- 48. A pneumatic hammer having a cylinder with ports andpassa es for the admission and exhaust of motive opposite ends, and apermanently-open supp emental exhaustort located intermediate the len thof thecyhnder in osition to be uncovere by the rear end of t e pistonshortly before the forward end ofthe piston-stroke, to thereby exhaustthe motive fluid behind the piston, and to be uncovered by the front endof the piston shortly after the initiation of the return piston-stroke,to thereby ex'- haust the motive fiuid in front of the piston.

49. A pneumatic hammer having a cylinder with ports and passa es for theadmission and exhaust of'motive uid to and from its opposite ends, and asupplemental exhaust port and passa e controlled by the piston andarranged to ex aust the cylinder on opposite sides of the iston, saidsupplementa passage extendin from the iston-chamber rearwardly anlongitudinal y through the cylinder-Wall to the main or regularexhaustport adjacent the rear end of the hammer.

IOO

by the air uid to and from its we@ a3.-

50; A pneumatic hammer having a cylin- I der with ports and passages forthe admission and exhaust of motive iluid to and from its opposite ends,a valve for controlling said ports and passages, and means forexhausting the front end of the cylinder independentlyL of the valvebefore the piston approaches the rear end of its stroke.

51.v A pneumatic hammer having a cylinder With ports and passages forthe admission and exhaust of motive fluid to and from its oppositeendsa,valve for controlling said ports and passages, and meansindependent of the valve for exhausting the cylinder on opposite sidesof the piston at the rear end of its forward stroke and near thebeginning of its rearward stroke.

52. A pneumatic hammer having a cylinder with ports and passa es for theadmission and exhaust of motive uid to and from its opposite ends, avalve controlling said ports and passages and moved in one direction byair compressed by the flpiston and in the other direction by motive uidcontrolled by the piston, and means for exhausting the front end of thecylinder independently of said valve. Y

53. A pneumatic hammer' .having a cylinder with ports and passa es forthe admission and exhaust of motive uid to and from its vopposite ends,a valve controlling said ports and passages andmoved in one direction byair compressed by the iston and in the other direction by motive uidcontrolled by thepistonhand means independent of the valve forexhausting the cylinder .on opposite sides of the piston.

54. A pneumatic hammer having a cylinvopposite ends, and a valvecontrolling said ports and passages and having at its front end apiston-head governing the admission of the motive fluid to the rear endof the cylinder, said piston-head being arranged to permit leakage ofthe motive fluid to the rear end of the cylinder when the valve isinposition to otherwise cut off the supply of motive fluid thereto.

56. In a pneumatic hammer, the combination of a cylinder, avalve-bushing having ports and passages for the admission and exhaust ofmotive fluid to and from the cylinder, said bushin having acircumferential groove located adjacent the rear end of the cylinder andcontaining a constant supply of motive fluid, a valve operating in saidbushing and controlling said ports and passages, and a constantly openbut restricted passage between said groove and the rear end of thecylinder.

JAMES A. CARR, WILLIAM P. CARR.

